Thanks for following up. I will definitely take a look.
We were able to put in a workaround last week, which looks similar to what you are doing in the dev version. The edit was in xml-sitemap-feed/xml-sitemap.php , and I changed the XMLSF_NEWS_POST_TYPE from 'post' to 'any' as follows:
if ( !defined('XMLSF_MEMORY_LIMIT') )
if ( !defined('XMLSF_POST_TYPE') )
if ( !defined('XMLSF_NEWS_POST_TYPE') )
if ( !defined('XMLSF_NAME') )
if ( !defined('XMLSF_NEWS_NAME') )
After making the change, an /audio custom post type story indexed for the first time, so I think we're good for now.